1. Field of the Invention
The present invention is generally relates to an automated immunoassay analyzer and, more particularly, to a high throughput automated immunoassay analyzer which permits high volume assay of a broad range of analytes in bodily fluids.
2. Description of the Prior Art
An immunoassay is a well known laboratory method used to determine the amount of an analyte in a sample such as plasma or urine. It is based on the interaction of antibodies with antigens, and because of the degree of selectivity for the analyte (either antigen or antibody), an immunoassay can be used to quantitatively determine very low concentrations of drugs, hormones, polypeptides, or other analyte compounds found in a test sample. For many years, immunoassays were performed by hand by trained laboratory technicians.
More recently, many companies have begun producing automated immunoassay analyzers. Automating the immunoassay procedures can be onerous because of the large number of steps needed to be executed. For example, in a conventional scheme, a sample is mixed with a reagent and a solid support having a bound antigen or antibody, the sample is incubated such that the corresponding antigen or antibody in the sample and a labeled antigen or antibody provided in the reagent can be bound to the antigen or antibody on the solid support, then the solid support is thoroughly washed and the label (fluorescent, radioactive, chemiluminescent, or the like) is detected by an appropriate mechanism, and finally the analyte of interest (antigen or antibody) is quantified from the detected label.
Most of today's automated immunoassay analyzers are designed for "walk away" operation, where the technician loads sample containing tubes onto a carousel and presses a start button. Thereafter, the automated immunoassay analyzer mixes appropriate reagents (often stored aboard the analyzer) with the sample, performs incubating and washing operations, detects the label, and computes the quantity of analyte in the sample from the detected label and stored calibration curves. The entire operation is typically done under computer control, and in some automated immunoassay analyzers, bar coding is used to identify the sample under test. The results of the immunoassays are typically output onto computer paper for inspection by the technician, or they can be monitored and displayed in real time as described in U.S. Pat. No. 5,316,726 to Babson et al. The immunoassay instrument described in U.S. Pat. No. 5,316,726 employs assay tubes that are preloaded with the immunoassay beads before the tubes are placed on the instrument.
Another automated immunoassay instrument is described in a trade brochure published by Olympus (Biomedical Products Division), Wendenstrasse 14-16, 2 Hamburg 1, Germany, describing an automated enzyme immunoassay analyzer under model no. "PK310", which is a sequential batch-processing system using a reaction disc containing U-shaped reaction tubes. A bead storage unit is included on-board the instrument for loading of assay tubes on the instrument comprising a plurality of bead cassettes mounted on a carousel. Each bead cassette stores a plurality of solid support beads as a column on a spiral track, where the beads exit the bottom of the spiral track into an open-air holding receptacle adjoining the outside of the base of the bead pack. The dispensed beads are picked up by a vacuum-operated bead transport for feeding into a U-shaped reaction tube.
With respect to hospital and clinical laboratories performing large numbers of tests per month, e.g., at least 5,000 tests per month, immunoassay systems are demanded which can handle high volume LIS based test ordering while retaining the capability of accepting test orders and any prioritizations directly from an operator.